The present invention is related to an apparatus and a method for calculating refill amount of refrigerant.
Generally speaking, so-called “fluorocarbon” is conventionally used as refrigerants which are employed in refrigerating apparatus (cooling machines) such as, more specifically, refrigerators and air conditioners. As to fluorocarbon, there is an HFC series of new refrigerants in addition to a CFC series and an HCFC series of old refrigerants. These series of fluorocarbon own various problems as to destruction of the ozone layer, and warming trends in earth temperatures, so that there are duties to collect and recycling-use the above-described fluorocarbon. Also, such fluorocarbon which cannot be recycling-used must be firmly destructed.
On the other hand, the fluorocarbon of R410A, R407C, R404A, R507A, which is typically known as the new refrigerants, corresponds to such mixed refrigerants which are formed by mixing several sorts of single component fluorocarbon (R32, R125, R134a, R143a etc.) with each other in predetermined ratios. In addition, there is fluorocarbon R502 of the old refrigerant as the mixed refrigerant.
On the other hand, in the case that refrigerating apparatus using the above-explained refrigerants are utilized for a long time period, the refrigerants are leaked from joints of pipes, so that heat exchanging performance of the refrigerating apparatus will be lowered. Therefore, in such a case, after the refrigerating apparatus have been repaired, the leaked refrigerant components must be refilled into these refrigerating apparatus. In the case of such a refrigerating machine using a mixed refrigerant, amounts of additionally filled refrigerant components must be changed in accordance with such a condition that what sort and how degree of the mixed refrigerant components have been leaked.
Accordingly, JP-A-8-136091 proposes the mixed-refrigerant filling method capable of additionally filling the mixed refrigerant, by which while the measurement is made of such a relationship among the temperatures of the refrigerants, the sound velocities thereof, the pressure thereof, which have been filled into the refrigerating machine used as a refrigerator and an air conditioner, the necessary refrigerant components are automatically filled in such a manner that the concentration ratios of the respective refrigerant components calculated by employing these measured values are entered in a predetermined range.
There is such an important aspect that when a mixed refrigerant is filled into a refrigerating machine, concentration ratios of the respective refrigerant components of this mixed refrigerant must be entered into a predetermined range. However, there is another important aspect that since such a mixed refrigerant having a defined amount fitted to a capacity of this refrigerating machine is required with respect to this refrigerating machine, filling amounts of the respective mixed refrigerant components which have been reduced due to leakage of the refrigerants must be managed. However, the above-explained patent publication also does not clearly describe the controlling operation as to the filling amounts of the mixed refrigerant components. There is no way to grasp amounts of refrigerant components which are left in the refrigerating machine by merely measuring concentration ratios of mixed refrigerant components. As a result, for example, in such a case that the respective refrigerant components of a mixed refrigerant are equally reduced, leaked amounts of the mixed refrigerant components cannot be judged.
In other words, since there is no such a means for precisely judging a defined amount with a refrigerating machine, filling amounts must be judged based upon experiences of an operator by considering output data of a pressure meter and the like. Also, the following technical idea may be conceived. That is, in order to grasp a total amount of mixed refrigerant components which have already been filled into this refrigerating machine, all of these mixed refrigerant components are once extracted from the refrigerating machine so as to be measured. However, this technical idea may cause such a problem that a large-scaled apparatus is necessarily required and a plenty of working time is necessarily consumed.
In addition, as explained in the above-explained patent publication, three sets of measuring devices must be provided in order to individually measure temperatures of refrigerants, sound velocities thereof, and pressure thereof. Such an arrangement may require a large-scaled mixed-refrigerant filling apparatus. Moreover, a controller for automatically controlling additionally filling amounts of refrigerants, electromagnetic valves, and pipes must be made more complex, and must be made bulky.
Also, in order to measure the respective refrigerant component ratios from the relationship among the temperatures of the refrigerants, the sound velocities thereof, and the pressure thereof, a large number of analytical curves are required which have been measured by intentionally changing the three dimensions, so that there is another problem that the concentration calculating operations must be carried out in a complex manner. Then, in such a case that the respective component concentration of such a mixed refrigerant made by mixing three, or more refrigerant components with each other is measured, analytical curves having further cumbersome three-dimensional broad slopes are required, so that the measuring sequential operations become difficult. Moreover, even when such a mixed refrigerant made by mixing these refrigerant components in a new mixing ratio will be employed in a future, the conventional mixed refrigerant filling method cannot immediately accept such a mixed refrigerant whose analytical curve has not yet been prepared. Also, since the mixed refrigerants under the completely same conditions can be hardly measured by the three measuring devices, there is a certain limitation in measuring precision.
As a consequence, generally speaking, each of the respective operators has once extracted all of refrigerants filled in a refrigerating machine and then newly fills necessary amounts of mixed refrigerants instead of such an operation that these operators inject the refrigerant components into the refrigerating machine by using a large-scaled apparatus. This may cause cost for disposing/filling fluorocarbon to be increased.